Programmed line pitch printer

ABSTRACT

A carriage control system provides programmed selection between values of line pitch at which a printer is to operate. Selection of one or the other of two values of line pitch is made by detecting the presence or absence of a flag bit in the first address position of a carriage control buffer used to store coded representations of channel skip commands which determine the skip operations of the printer carriage.

United States Patent Frederick W. Schaaf Owego, N .Y.

May 15, 1968 Jan. 26, 1971 International Business Machines Corporation Armonk, N.Y.

a corporation of New York Inventor Appl. No. Filed Patented Assignee PROGRAMMED LINE PITCH PRINTER I 3 Claims, 27 Drawing Figs.

u.s.c| 197/133 Int. Cl B4ljl5/00 Field otSearch 197/19,20,

References Cited UNITED STATES PATENTS 2/1919 Corcoran 2,659,472 11/1953 Stimson 197/133 2,747,717 5/1956 Cunningham et a1 197/133 2,831,561 4/1958 Speh.......... 197/133UX 3,094,261 6/1963 Thompson. 197/133X 3,272,303 9/1966 Pohl 197/114 3,280,957 10/1966 Thiel 197/114 3,326,348 6/1967 Cralle et a1. 197/114 3,354,816 11/1967 Giannuzzi Primary Examiner-Ernest T. Wright, Jr. Att0rneysl'lanifin and Jancin and Francis V. Giolma ABSTRACT: A carriage control system provides programmed selection between values of line pitch at which a printer is to operate. Selection of one or the other of two values of line pitch is made by detecting the presence or absence of a flag bit in the first address position of a carriage control buffer used to store coded representations of channel skip commands which determine the skip operations of the printer carriage.

PATENTEDJANZSIQYI v 33551929 sum 010F24 IN VE N TOR FREDERICK w. SCHAAF ATTORNF Y PATENIEuJAnzslsn 3557.929

saw us or 24 FIG. 2 h

VOLTAGE SENSE LEVEL CARR/AGE Q CONTROL BUFFER PATENTEUJANZBIBYI 0 3557,9291

sum 18 0F 24 00/ /00/ 1/0 00/ 00/ 00 00 i 1760 00/ 00/ 00000 0 I 00/0 0000 0000/00 & 0000000 00/ 00/0 mo comm/m0 0000 00/0/00 s0/2 REJECT 0000 000/000 00/// 15a m0 0 00/ 005/ WW0! 139 I 83 0000 0/00 00 1000000 00/ 0/00 000000 mb 5b 0/10/00 000 0000 000/000 00/ INVALID 173a 000$ 000$ LATCH 0000/00 0050/ INVALID A763. CCB 00/ 000 000//r/--- CCB 0 LOAD PARITY LATCH LATCH 0 v H6b i 173 e 17)6e Li 0400000 000000; CAR|AGE 5750 0 FAILURE LATCH 00/000 00/ 00/ 0 2 mo 000/0 000 000 0000/ I 0R FIG. 2q 

1. In a line pitch control system controlling the amount of movEment for each line advance of a printer carriage having drive means operated in a step-by-step manner by pulses to actuate said carriage to advance a document on which a printer operation is to be performed a fixed increment less than one line for each of said pulses; means for applying an initial pulse to said drive means to cause it to step; means including a line counter operable to determine the number of lines the carriage advances; means responsive to each step of said drive means connected to said drive means to apply additional pulses to said drive means; carriage counting means connected to said drive means to count said initial and additional pulses for each line advance; stop means connected to said line counter and said carriage counting means controlled by predetermined counts of said carriage counting means and said line counter, and connected to said drive means to apply a predetermined number of stop pulses to said drive means and to render said additional pulses ineffective; and line pitch control means including a programmable storage device connected to said carriage counting means by circuit means responsive to the presence or absence of a control bit in said programmable storage device to selectively condition said carriage counting means to count different numbers of pulses before reaching said predetermined count for advancing the document different amounts for each line advance before effecting application of said stop pulses, to effect different line pitch advances.
 2. The invention as defined in claim 1 characterized by said line pitch control means comprising a bistable circuit element having two operating conditions and being connected to said carriage counting means to preset said carriage counting means to one initial count in response to detecting said control bit in one storage position of said programmable storage device and to preset said carriage counting means to another initial count in response to detecting the absence of a bit in said one storage position.
 3. The invention as defined in claim 2 characterized by said programmable storage device comprising a carriage control buffer storage device, said bistable circuit element comprising a line pitch latch, and said circuit means including an address 1 latch connected to said storage device and said line pitch latch to detect a bit in the address 1 position of said carriage control buffer storage device for setting said line pitch latch, the absence of a bit being used to reset said line pitch latch. 